两点法T2-DIXON图像局部水-脂分离错换的解决方法  

Methods for solving the neck two-point T2-DIXON fat-water separation misalignment

作　　者：邓和平[1] 任静[1] 王闽[1] 后军民[1] 董晓蕾[1] 陈晓丽[1] 黄叶才[1] 陈晓煜 Deng Heping;Ren Jing;Wang Min;Hou Junmin;Dong Xiaolei;Chen Xiaoli;Huang Yecai;Chen Xiaoyu(Department of Radiology, Sichuan Cancer Hospital and Institute, Chengdu 610000, China)

机构地区：[1]四川省肿瘤医院研究所影像诊断部,成都610000

出　　处：《中华放射学杂志》2018年第6期467-471,共5页Chinese Journal of Radiology

基　　金：四川省卫生计生委科研基金项目（130229）

摘　　要：目的探讨鼻咽部和颈部两点法T2-DIXON图像局部水-脂分离错换的解决方法。 方法前瞻性收集2015年8月至2016年11月四川省肿瘤医院，行鼻咽部、颈部T2-DIXON轴面检查出现局部水-脂分离错换且检查部位无金属植入物的140例患者。将患者采用随机数字表法分为7组，每组20例，再次采用以下方案进行T2-DIXON轴面扫描。A组采用方案1（局部水-脂分离错换层面增加匀场块）；B组采用方案2（将T2-DIXON序列重复采集次数增加为2次）；C组采用方案3（在扫描部位放置匀场辅助装置）；D组采用方案1＋方案2；E组采用方案1＋方案3；F组采用方案2＋方案3；G组采用方案1＋方案2＋方案3。对比2次扫描的图像质量，进行图像质量分级；并分别测量各组2次T2-DIXON序列扫描图像未出现水-脂分离错换同一解剖位置的肌肉组织信噪比（SNR）。7组间患者SNR的差异采用单因素方差分析比较（组内两两比较采用SNK法），图像质量分级的差异采用秩和检验比较（两两比较采用Nemenyi法）；采用配对t检验比较同组患者两次扫描图像SNR的差异。 结果7组的图像质量均有不同程度的改善，A^G组图像质量分级达到3级及以上者分别为12、15、15、16、17、18、18例，采用单一方式进行扫描对图像质量的改善效果不如采用2种及以上方式组合的效果。A、C、E组两次扫描的SNR差异无统计学意义（P均〉0.05）；B、D、F、G组两次扫描的SNR差异有统计学意义（P均〈0.05）。7组间图像质量分级的差异有统计学意义（P〈0.05），G组图像质量最优；7组间第1次扫描的SNR差异无统计学意义（P〉0.05），第2次扫描的SNR差异有统计学意义（P〈0.05）。 结论MRI扫描出现水-脂分离错换时，通过采用局部层面增加匀场块、增加重复采集次数、局部放置匀场辅助装置的方法可以改善图像质量，联合采用上述方法的效果优�ObjectiveTo explore the methods for solving the neck two-point T2-DIXON fat-water separation misalignment. MethodsDuring August 2015 to July 2016, 140 patients with fat-water separation on the nasopharynx and cervical axial T2-DIXON images were prospectively recruited from Sichuan Cancer Hospital. There was no metal implant in the fat-water separation misalignment area. The patients were divided into 7 groups by random number table method with 20 patients in each group for the axial T2-DIXON scan： Group A adopted plan 1（increasing localized shim box on the fat-water separation misalignment area）;Group B adopted plan 2（increasing the times of repeated acquisition to 2 of the T2-DIXON sequence）;Group C adopted plan 3 （placing the shimming assist device on the inspection area）;Group D adopted plan 1＋ plan 2;Group E adopted plan 1＋ plan 3;Group F adopted plan 2＋ plan 3;Group G adopted plan 1＋plan 2＋ plan 3. The images quality of two scans were graded and compared. We compared the signal-to-noise ratio （SNR） of T2-DIXON image on the same muscle tissue between the two scans of each group. The difference of SNR on the two scan images was compared with the paired t test, the difference of SNR among seven groups was conducted with independent sample t test, and the comparison of image quality classification was conducted by rank sum test. ResultsThe image quality of all the seven groups was improved to some different degrees. The cases with image quality reaching level 3 were 12, 15, 15, 16, 17, 18 and 18 in A to G groups, respectively. It was better to use the combination of two or more methods to improve the quality of the image than to use a single method. There were no statistically significant differences in SNR between two scans in A, C and E group （all P〉0.05）.There were statistically significant differences in SNR between two scans in groups of B, D, F and G（all P〈0.05）. There were statistically significant differences among the 7 groups, with the best quality in G gro

关 键 词：磁共振成像 两点法DIXON 水-脂分离错换 

分 类 号：R445.2[医药卫生—影像医学与核医学]